This application claims the priority of Application No.103 25 653.9 filed in Germany on Jun. 6, 2003, the disclosure of which is expressly incorporated by reference herein.
The invention is based on an air-conducting device for a motor vehicle. Preferred embodiments of the invention relate to an air-conducting device for a motor vehicle, having an operating element and a spoiler lip extending completely or partly over the vehicle width, by means of which operating element the spoiler lip can be displaced from a moved-in inoperative position into a moved-out operative position, and which spoiler lip comprises an elastic and extensible material.
From German Patent Document DE 101 60 748.2 (corresponding U.S. Published Application No. 2003/116996) which is a later publication, an air-conducting element of the above-mentioned type is described which has an operating element for a spoiler lip, which spoiler lip extends completely or partly over the vehicle width. By means of the operating element, the spoiler lip can be displaced from a moved-in inoperative position into a moved-out operative position, an elastic and extensible material been selected for the spoiler lip.
It is an object of the invention to optimize an air-conducting device of the initially mentioned type.
This object is achieved according to certain preferred embodiments of the invention by providing an air-conducting device for a motor vehicle, having an operating element and a spoiler lip extending completely or partly over the vehicle width, by means of which operating element the spoiler lip can be displaced from a moved-in inoperative position into a moved-out operative position, and which spoiler lip comprises an elastic and extensible material, wherein the spoiler lip is made of a fiber composite material with a matrix of the fiber composite material being extensible and elastic, wherein a first fiber group has fibers embedded in the matrix, which fibers extend extend transversely to a direction of the vehicle width and transversely to a direction of the width span of the spoiler lip, and wherein the fibers of the first fiber group are essentially inextensible.
Further advantageous features of preferred embodiments of the invention are described herein and in the claims.
Important advantages achieved by means of certain preferred embodiments of the invention are that, by means of the essentially inextensible fibers of the first fiber group, a spoiler lip is provided which is dimensionally stable particularly in the moved-out operative position and which, also at high driving speeds and correspondingly high air pressure forces, is hardly or insignificantly deformed, whereby the desired aerodynamic effect of the spoiler lip is maintained. As a result of the inextensible fibers with the alignment according to the invention transversely to the width span of the spoiler lip, the extensibility of the spoiler lip in the direction of the width span is maintained, which is advantageous particularly for motor vehicles with a rounded shape of the forward structure. By means of the use of the fiber composite, the spoiler lip is more resistant in the event of an influence of foreign bodies, so that, in addition, the operating element is shielded by the spoiler lip.
According to a further development of certain preferred embodiments of the invention, the matrix of the fiber composite material is reinforced by a second fiber group which has fibers extending in the direction of the width span of the spoiler lip and being elastically extensible. The stability of the spoiler lip is further improved in that the extensibility is maintained in the direction of the width span. In addition, as a result of the elastically extensible fibers of the second fiber group, higher restoring forces can be provided for the spoiler lip if, during the movement from the inoperative into the moved-out operative position, the latter is stretched into the direction of the vehicle width.
In order to further increase the dimensional stability of the spoiler lip in the moved-out operative position, in certain preferred embodiments of the invention, at least one bending-elastic element extending along the vehicle width is arranged at a free end inside the spoiler lip.
As a result of the fact that the fibers extend at least partially around the bending-elastic element in certain preferred embodiments of the invention, the spoiler lip receives a high dimensional stability also in the area of its free end.
A simplification with respect to the manufacturing of the spoiler lip is achieved by providing that the fiber roving is caused to extend around the bending-elastic element.
According to certain preferred embodiments of the invention, the fibers of the first fiber group extend to the bending-elastic element and therefore the dimensional stability of the spoiler lip is reduced in a defined area, specifically the desired bending area, whereby the spoiler lip can be displaced in a hinge-type manner out of the inoperative into the operative position and back.
According to certain preferred embodiments of the invention, the operating element is operated pneumatically and is formed by a hose which extends at least in sections along the vehicle width, which hose has at least one inflatable chamber and is made of an extensible and elastic material. Particularly the material of the matrix of the fiber composite material of the spoiler lip is used for this purpose. Such an inflatable operating element, which is evacuated in the inoperative position and can therefore be folded together, has a low space requirement and nevertheless ensures sufficient operating forces in order to be able to change the spoiler lip into the moved-out operative position. During the evacuation of the hose or of the chamber, the above-mentioned restoring forces are active which were built up in the spoiler lip itself, which spoiler lip is thereby automatically displaced from the operative position back into the moved-in inoperative position and thereby folds the hose or the chamber.
So that the hose or the chamber can be filled with a sufficiently high pressure, a fiber reinforcement for the wall of the chamber or of the hose is provided according to certain preferred embodiments of the invention.
According to certain preferred embodiments of the invention, the fiber reinforcement for the wall of the chamber or of the hose is formed by essentially inextensible fibers, as they are used for the first fiber group. The fibers extend in the wall at least partially around the chamber or the hose. The fibers limit an inflating of the chamber or of the hose in the radial direction, so that, independently of the action of pressure upon the hose or the chamber, a desired inflating cross-section of the operating element is not exceeded. Thus, in its operative position, the spoiler lip will take up the same position during each operation.
According to certain preferred embodiments of the invention, the desired bending area is constructed adjacent to the fastening section, the fibers of the first fiber group are laid into the fastening section whereby the spoiler lip can be returned in a flap-type manner from its inoperative position into the moved-out operative position and back.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.